(a) Field of the Invention
The present invention relates to a thin film transistor array substrate and a manufacturing method thereof.
(b) Description of Related Art
An active type display device, such as a liquid crystal display (LCD) or an organic light emitting diode (OLED) display, includes a plurality of pixels arranged in a matrix, each pixel including field generating electrodes and switching elements. The switching elements include thin film transistors (TFTs) having three terminals, a gate, a source, and a drain. The TFT of each pixel selectively transmits data signals to the field-generating electrode in response to gate signals.
The display device further includes a plurality of signal lines for transmitting signals to the switching elements. The signal lines include gate lines transmitting gate signals and data lines transmitting data signals.
Both the LCD and the OLED include an array substrate provided with respective ones of the TFTs, the field-generating electrodes, and the signal lines. The described array substrate may be referred to as a TFT array substrate.
The TFT array panel has a layered structure that includes conductive layers and insulating layers. The gate lines, the data lines, and the field-generating electrodes are formed using various conductive layers separated by insulating layers.
The TFT array panel having the layered structure is manufactured using several lithography steps followed by etching steps. Since each lithography step incurs monetary and time costs, it is desirable to reduce the number of the lithography steps used in manufacturing the TFT array panel.